


The Mechanics of Rest

by Isagel



Category: Rogue One: A Star Wars Story (2016)
Genre: Caretaking, Dominance, Droid Sex (Star Wars), First Time, Friendship, Held Down, M/M, Pre-Rogue One, Robot Feels, Robot Sex, Robot/Human Relationships, Size Difference, Size Kink, Submission, Warm and Fuzzy Feelings
Language: English
Status: Completed
Published: 2020-11-15
Updated: 2020-11-15
Packaged: 2021-03-09 20:34:20
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,099
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27582104
Author URL: https://archiveofourown.org/users/Isagel/pseuds/Isagel
Summary: After a mission, Cassian is too keyed up to rest. K-2 finds a way to help him unwind.
Relationships: Cassian Andor/K-2SO
Comments: 28
Kudos: 96
Collections: JoyFest 2020





	The Mechanics of Rest

**Author's Note:**

  * For [longwhitecoats](https://archiveofourown.org/users/longwhitecoats/gifts).



> Written for the prompt "Cassian Andor has robot sex with his robot friend K-2SO and it's one of the few times he can completely relax." Pretty much exactly what it says on the tin.
> 
> Contains brief descriptions of past mission-related violence and some dark thoughts on Cassian's part about the lives they lead.

“I am aware that organics are fond of unnecessary energy expenditure,” K-2SO says, “but this constant back and forth is making my optic processors glitch.”

Cassian stops short, halfway through the circle he’s been pacing across the warehouse floor, and looks at his friend. The droid is standing up against the wall, next to the bedroll Cassian has laid out for himself on the concrete floor. His straight, still posture is the one Cassian has come to associate with his cycles in power saving mode, but his optics are gleaming flashlight bright in the dimness of the large room, tracking Cassian with his usual steady observance.

“It’s still five hours until this planet’s dawn,” K-2 adds. “Using them for rest would be advisable.”

“Yeah.” Cassian lets out a sigh, runs his hand through his hair. It’s damp with the heavy rain still coming down against the metal roof above. Storm season on the single inhabited planet in the Detera system, very far from Yavin 4, from comrades and backup and the secure perimeter defences of Rebel Alliance HQ. He _is_ tired. “You’re right. There’s nothing more we can do until Draven’s courier makes contact in the morning.”

He steps over to their campsite, into the soft glow of light from his portable lantern, turned low to keep their presence hidden, though no one is likely to pass through this abandoned industrial sector on a shitty night like this. He strips his jacket off, rolls it up to use as a pillow, the fabric wound tight around the datastick in his inner pocket, the reason they came to this distant corner of the Outer Rim, the intel they’ve been chasing for weeks. He’s feeling a bit lightheaded with it, the exhilaration and relief of a mission accomplished, his body still riding the adrenaline wave of all that planning and prowling released into action, like a ship spinning through the vacuum of space long after the engine’s been cut. He’s usually good at snatching his rest when he can, though, in any circumstances; he just needs to find the calm.

He lays the jacket down at the head of his bedroll, the end nearest K-2’s heavy feet, and shoots the droid a smile as he sits down with his back against the wall. K-2 tilts his head but makes no comment. 

Cassian digs a ration bar out from his backpack, chews it down and chases it with water from his canteen. The rain is getting louder, a rapid needlepoint spray of noise above his head; his fingers tap in rhythm against the bottle. There are scratches on the back of his hand, he notes, from the last fight he’d almost lost tonight, the datastick already in his pocket then, but his exit blocked, too many men for him to drop them all with his blaster before one closed on him, tackled him to the ground as the last of the others cried out from his shot, and they wrestled for the weapon, the world narrowed to the clear, sharp desperation of physical struggle. His opponent clawed the blaster out of his grip, but that was the opening Cassian needed, a moment of distraction as the man suddenly felt safe, and Cassian could surge up, twist them around, lock his arms around the man’s neck and press until he heard it snap. When he staggered to his feet, Kay was there, standing huge in the doorway beyond the bodies on the floor, the twisted wreckage of the door he’d torn down dangling from his metal fingers, the rain pouring in around him. Cassian’s way out.

Cassian screws the cap back on the bottle, sets it on the floor. His muscles are too tense, his pulse too loud in his own ears, his body jittery with the awareness of being alive. He can’t bear the thought of lying down and being still. Instead he pushes to his feet, automatically adjusting his blaster in the holster at his side, and starts walking the perimeter again.

“Cassian?” K-2 asks.

Cassian waves a reassuring hand in the air, doesn’t turn around.

“It’s all right, you can power down. I’ll take the first watch.”

The warehouse is as empty as it was on his first lap around the room, the shadows deep when he gets further from their camp. The air is chilly without his jacket, rain-wet strands of his hair brushing against the back of his neck, making his skin break out in goosebumps. Everything is quiet, apart from the incessant background noise of water falling, falling, falling. He wonders if anything is left standing when the dry season comes, if there is anything not hollowed out and washed away by the flood. He shivers, raps his fingernails against the grip of his blaster. They’re not going to be around long enough to find out.

He rounds the supporting pillars near the far end of the warehouse, stepping around the corner to head back, and almost walks right into K-2, blocking his path. He’s known the droid long enough to learn a seven foot hunk of metal can move much quicker and more silently than you’d expect, when the situation calls for it, but it still throws him, every time. A sharp exhale of surprise escapes him.

They’re close together, collision just barely avoided, and at this distance K-2 is a solid wall of metal, immovable. Cassian has to tilt his head back, and further back, to look him in the face. It leaves him suddenly exposed, a sense of vertigo tightening his throat.

“Cassian,” K-2 says, in his slow, soft, logical voice, “I have run the analyses. There is only a 2.15 percent risk that anyone will find us here before morning, and if they do, my sensors will pick up their approach much sooner than your eyes and ears, even if I am in low power mode. There is no usefulness in you keeping guard. You have considerable strategic understanding for an organic, you must be aware of this yourself.” He grabs Cassian by the upper arms, wide palms spanning his biceps, long metal fingers closing, full circle, around his limbs, tight as cuffs. Cassian knows that a droid’s face can’t show expressions; he also knows the expression on K-2’s face is concern. “It’s been 37 hours since you slept,” his friend observes. “Organics cannot function adequately without sleep.”

Cassian is about to point out that he has survived being awake considerably longer than that, in far worse conditions, when K-2 picks him up. Simply lifts him straight up off the ground, as though he weighs nothing, and carries him in a few long strides back to their camp. The unexpectedness of it snatches the words out of Cassian’s mouth, his brain struggling to catch up with the change in perspective, his eyes for a brief, dizzying moment level with the white, clear light of K-2’s optics, blinded by it, and then K-2 deposits him on the floor again, his feet on the soft mat of his bedroll. He sways, footing uneven, and Kay holds him upright, keeps holding on, no give at all in the grip on his arms. 

Secure. 

Heat flares at the base of Cassian’s spine. His breath is coming faster. He wets his lips with his tongue.

K-2 tilts his head, a quiet whirr of machinery as his joints shift. 

They look at each other.

“Cassian,” K-2 says. “This physical reaction you often display when I touch you, I’ve been trying to figure it out. Is it human arousal?”

The bluntness of the question is like a gut punch, but of course K-2 is blunt, about this as with everything else. And Cassian may be a spy and an assassin, a master at hiding and deceiving, but if there is one person he is honest with, it’s Kay.

“I wasn’t sure you could tell,” he says. The corner of his mouth quirks; he doesn’t know if the smile comes off as charming, embarrassed, or simply a nervous tic.

“The dilated pupils and the rapid heartbeat could indicate fear,” K-2 muses. “But you’re not afraid of me.” No doubt there at all, despite K-2’s origins, despite the way some people even on Yavin 4 look askance at his appearance, wary of the imperial crest on his shoulders. It makes a warmth spread in Cassian’s chest, to know that K-2 sees the trust he feels, to know that it is mutual.

“No,” he agrees. “It’s not fear.”

K-2 studies him. His fingers flex around Cassian’s arms, shift, as if feeling out the shape and density of his skin and muscle, of the bone beneath. It’s not unlike being caressed.

“You know I’m not a pleasure droid,” K-2 says. A question there, though it’s phrased as a statement.

 _No,_ Cassian thinks. _You’re like me. Fashioned to kill and destroy._ There is a gleaming knife edge in that thought, its cut all too familiar, but also a tenderness that leaves him reeling.

What he says out loud is:

“I wouldn’t want you to be.”

Kay appears to consider this.

“If I were a pleasure droid, I’d be programmed to provide for your every desire.” Thinking out loud, Cassian judges, the way he does when running available data through his processors, trying to break a situation down into manageable, usable numbers. “I would do whatever you told me to do, to please you.” Another stretch of silence, the rain loud in the quiet, all around them in the dark. The idea of that other K-2SO hanging between them—someone pliant, subservient. Then Kay tilts his head, looks at Cassian from a different angle. “You never show these reactions when I’m following orders,” he observes.

And here Cassian had thought the droid couldn’t tell when his knees went weak.

“The few times you actually do what you’re told,” he quips. “I’m too busy being astonished to feel anything else.” 

The sarcasm is easy, familiar camouflage. Beneath it he feels stripped down, laid bare, too exhausted and wired and wanting to know how to handle this, to know what Kay will decide to think of him, when he’s reasoned it all through. He knows what kind of humans keep pleasure droids; if Kay starts to see him like that after all—

“I’ve heard,” Kay says, “that most organics find sexual climax relaxing. Is that accurate?”

The question throws him, an unexpected change of tracks.

“I— Yeah, I guess. It releases a lot of good chemicals in your body, it can make people pretty mellow.”

“Would it have that effect on you?”

Oh. They’re right back to where they started, not on a new track at all. K-2 never does let anything go. But—

“Kay, just because I...find you attractive, that doesn’t mean I expect anything to happen between us. I know you can’t feel what organics feel. I don’t want you to let me do anything you don’t enjoy. I don’t want to use you.”

K-2 makes a soft, metallic humming noise.

“The Empire used me,” he says, “to kill without reflexion, when my programming constrained my ability to analyse my orders or choose whether to follow them. You made sure I am free to disregard any orders I find flawed, which, of course, leaves very few directives I’m compelled to obey. I am with you, here, because I want to be.”

Cassian swallows, tries to control the emotions constricting his throat. 

“Me, too,” he says, barely more than a whisper. Such a little thing, and too large to admit in a world where any day can be the one that claims his life for the rebellion. “I want to be with you, too.”

K-2 lifts his hand, places it on Cassian’s cheek, the gentlest touch of hard metal.

“Cassian,” he says. “It would be highly satisfactory to me if I could make you relax. If I could _make_ you be still.”

The emphasis of the words travels like a shockwave down his spine, leaves him raw and open with hunger.

He turns his head, mouths at the base of Kay’s thumb. There are tactile sensors in the droid’s hands, sensitive clusters, to operate machinery, computers, weaponry—it’s not like kissing human skin, but he knows Kay feels it, can register the heat of his lips, their eagerness. The metal is smooth, not cool but warm, always warm from the friction of parts working together, from processors running the sharp, stubborn operating system of Kay’s mind, the functions of his thoughts. Cassian licks into the crevice of a joint, looks up at Kay through his lashes, with the hint of a smile. Challenging.

“Do your worst, then,” he says.

K-2 lays his hands on Cassian’s shoulders, lets him feel their weight, pressing down.

“I asked you before to lie down, Cassian.” 

He isn’t asking now, and Cassian’s knees buckle before the words are even out. He is hard already, and the act of kneeling stretches the fabric of his pants tight over his erection, making him gasp. K-2’s fingers tighten on his shoulders in response, thumbs digging into the hollows above his collarbones hard enough to bruise. The inhuman pressure only lasts a second before Kay lets up, but Cassian wants to chase it, dissolve beneath it.

“Put your blaster aside,” Kay says, and Cassian fumbles with the fastenings of his holster, pushes the weapon safely out of their way on the concrete floor as he stretches out on the bedroll. 

He lies back with his head on his balled-up jacket, feels the datastick at its center, a talisman of hard-fought victory and hope tucked inside his pillow. K-2 follows him down, moves to straddle his body and kneels down on all fours, his long, spindly limbs fencing Cassian in, the heavy, solid mass of him hovering above, so close.

Cassian reaches up and runs his palms over Kay’s chassis, stroking smooth metal, his skin catching in the scratches and dents left by the battles they’ve fought together, by the tight spots they’ve been in and their narrow escapes. He hooks his fingers over the upper edge of the chest plate, dipping inside the opening where Kay’s neck protrudes, a strange and intimate touch. He isn’t sure whether he means to pull Kay in or hold him back, if he’s trying to rush forward or let his reason catch up.

“Kay,” he says, “don’t take this the wrong way, I just have to check... Do you know what you’re doing?”

“I have collected relevant data. I believe I have an adequate understanding of the kind of stimulation required. And I assume you will correct me if I do something wrong.”

 _Stimulation._ Force, just the idea makes him squirm.

“I will,” he promises. “And you, too, right? You will tell me if I do something you don’t like?”

“Cassian,” Kay says, “I thought I was being clear—” He sits back on his haunches and wraps his hands around Cassian’s wrists. “You are not _doing_ anything at all.” He tugs Cassian’s grip loose and pulls his arms up over his head, presses his hands down into the floor. “You are being still.”

Cassian can’t help it, it’s pure reflex to move against the hold, tighten his muscles to test it. Kay’s grip is like a vice, any effort Cassian could make to pull free ridiculously futile against his machine strength. 

An unbreakable restraint.

Safe.

He feels himself go pliant, yielding, even as his hips arc upward, his cock throbbing with need for friction, for touch. 

“You like this,” Kay says. His voice has the same note of self-congratulation he uses when his probability calculations are proved right down to the third decimal place. It’s infuriating. It makes Cassian want to rub himself over Kay’s body like a Pterian fhalla-beast in heat.

“I would like it even more if you touched me,” he snaps.

“That is my working theory,” Kay agrees. “You are more impatient than I anticipated.” 

But he pulls Cassian’s wrists together, close enough that he can hold them with one hand, and reaches down to tug the hem of Cassian’s shirt up, exposing skin. His fingers trail over Cassian’s belly along the waistband of his pants, a light scratch of sharp-edged metal fingertips that sends shivers of anticipation through his nerves. Then Kay’s touch dips lower, and he feels the top button of his fly eased open.

“Yeah,” he breathes, “yeah, come on.”

He bites his lip, trying to keep still as Kay undoes his clothes, feeling that almost brush against his hard-on with every button, until it’s done, and Kay yanks his pants down with one sharp pull, and his cock springs free.

Kay lays his hand on the bare curve of his hip, palm hard against hip bone, fingers digging into the flesh of his ass. The grip holds him down just as firmly as the hand around his wrists, his body drawn taut between two anchor points, each shaky breath he takes stretching his sinews and muscles against their weight. He feels aware of every cell in his body.

Kay strokes his thumb through the coarse hair at the base of his cock, back and forth, as if studying the texture. He bends his head to look down the length of Cassian’s body, the sudden absence of his bright optics shining in his face leaving Cassian blinking. Kay’s hand shifts, and there is metal stroking over his balls. He moans at the touch, then curses under his breath as Kay’s finger lightly, lightly trails up his cock.

“Human genitals are very sensitive,” Kay observes. “That time a stormtrooper kicked you here, you couldn’t walk for half an hour.”

Cassian’s balls clench at just the memory, or maybe it’s Kay’s touch causing that, the careful slide of metal against skin.

“As I recall, that didn’t end well for the stormtrooper.” He raises his head to look down, too, following Kay’s gaze to where the droid’s hand touches his naked flesh. The droid’s hand that only this afternoon tore a solid steel door off its hinges to get to him. He smiles, lets the joke show in his voice. “You’re not going to kick me in the balls, are you?”

Kay’s processors make a sharp whirring sound.

“I don’t intend to hurt you.” The insecurity is unspoken: _But you’re fragile and I’m worried that I will._

“You won’t,” Cassian reassures him. “I know you won’t.” He takes a deep breath, tries to sound steady. “Wrap your hand around my erection, loosely. Yeah, like that.” _Force._ His whole cock is covered by Kay’s huge fist, encased from tip to root in warm, unyielding metal, lost in it. He grows harder at the sight, swells and thickens inside Kay’s grip, fluid leaking from him, hot and slippery. “Tighten your grip now. Slowly. I'll tell you when it’s tight enough. Oh, that’s good, Kay.”

He lets his head fall back on his pillow, and Kay presses his hands down firmer against the floor, reasserting his hold. The droid’s fingers squeeze tighter and tighter around his cock, an incremental increase in pressure, crushing strength perfectly controlled. It builds, and builds and keeps building, making him pant and whimper, until at last, at that edge where overpowering pleasure very nearly tips over into pain, he says “Stop,” and K-2 goes motionless. He’s looking down into Cassian’s face again, his head at an angle, and Cassian knows without asking that he’s saving the data to his memory, the exact force per square inch safe to apply to Cassian’s erection stored away in his data bank, and the idea of that is what finally makes him lose his own control.

He tries to move, tries to fuck up into Kay’s hand, desperate for friction, but even holding him, Kay’s fist is still weighting his pelvis down, and he can find no purchase, no leverage to shift his hips.

“Please,” he breathes, “please, Kay, I need—”

“Manual stimulation?” Kay suggests. He sounds smug again, the moment of uncertainty past. “Like this?” 

His hand starts moving. Slowly, up and down, maintaining the same exact level of pressure, a steady, mechanical motion. Cassian can feel the flat surface of his palm sliding up his shaft, the smooth, cylindrical joints in his fingers dragging across his skin, his own precome a lubricant spreading between them, easing the way, seeping into the hinges of K-2’s machinery, their parts slotted together, his and Kay’s, organic and robotic. There is a rightness to it that takes him by surprise, that is entirely expected. He turns his neck, seeking contact, presses his face into Kay’s forearm stretched above his head to hold him in place. His body is shaking with pleasure and he breathes it out in ragged breaths against the metal, in open-mouthed kisses that fill his palate with the sharp, clear taste of steel.

“Faster?” Kay asks, and his voice is in Cassian’s ear, his head bent so low his forehead brushes the hair at his temple; the space between them closing, a gravitational pull.

Cassian’s reply is more a moan than a spoken word, but Kay understands him. His hand picks up the pace, rubbing Cassian’s cock with quicker strokes, firm, insistent. It’s been too long since Cassian even touched himself like this, with the intent to get off, let alone had another person do it for him—sex another physical need, like sleep, that he shoves away when all his mind can see is the job, the mission, everything that rides on surviving long enough to see it through—it won’t take much of this to push him over the edge. It feels so good, what Kay is doing, the nearness of him, the way his giant body is everywhere around him, above him, filling his senses, blocking the rest of the galaxy from view. There’s nothing here but the two of them, and the pleasure building at the base of his spine, tightening his balls. Here and now, there’s nothing else that matters.

“Cassian,” Kay says, and it’s that familiar bluntness again, the perfect openness that leaves him breathless, after all his years carrying secrets, paying for them in blood, “I want to see you climax. Will you show me?”

It yanks a laugh out of him, the idea that at this point he could not. Or perhaps it’s joy, bubbling out of him, that Kay wants this, wants him like this, wants them together. Either way, he doesn’t have a chance to reply before Kay starts jerking him faster still, a speed so fast the touch is more like vibration, an inaudible chord travelling through every nerve-ending, reaching into the marrow of his bones, deeper than all his layers of deflection and deceit, beneath any defences. He comes helplessly, artlessly, arching up from Kay’s grip, arching into him, and Kay holds him there, holds him fast in the moment, and all he can do is be.

* * *

Later, it’s still raining, as it has been for weeks before they landed on this planet, as it will be for months after they leave. Cassian lies in the dark and listens to it, his head tucked against Kay’s leg where the droid sits propped against the wall next to his pillow. Kay’s hand is in his hair, stroking absently, though his optics are dimmed to their lowest setting. Cassian feels boneless, wrung out with pleasure and with two days of being awake, with weeks of chasing their target, all of it catching up to him the moment he let go. He yawns and pulls his blanket closer around him.

“Thanks, Kay,” he says. “I did need that.”

“Any time,” Kay says. “I’m pleased my analysis of the situation was accurate.”

“Me, too, buddy.”

He wants to ask what ‘any time’ entails, if it means he can have this in a clean, warm space when he’s well-rested enough to suggest all the ways of doing it he can imagine and take his time exploring them all in turn, if it means Kay will tell him when and how, like tonight. But the question isn’t pressing. He knows he will wake up with Kay next to him in the morning, that whatever new orders Draven's courier brings from the Alliance, they’ll deal with them together. That’s more than enough for now.

The tapping of the rain against the roof sounds softer than before, a temporary lull in the storm. Or perhaps he is the one who is calmer, ready to hear a gentler rhythm.

He closes his eyes and lets the falling raindrops sing him off to sleep.


End file.
